This invention relates to the electronic reproduction of images and, more particularly, to novel and highly-effective methods and apparatus facilitating high-quality halftone reproduction of images in color or black and white for use in the printing art.
For many years the reproduction of images for use in the printing art was done without the benefit of electronics. Recently, electronic reproduction techniques have been developed, including means for halftone reproduction.
Modern electronic screening techniques obviate the physical devices such as halftone screens otherwise required in order to form the dot structure. Even the most advanced techniques heretofore have suffered, however, from serious deficiencies. For example, in conventional practice, the locations of the dots and the features of the images have an essentially random relation with respect to each other. This randomness results in a visible roughness, serration, or fuzziness of feature edges that should be smooth and sharp. Various proposals have been made for modifying the dot structure so that the edges of features in the images are made sharper, but the best dot structure heretofore acheived leaves a roughness or fuzziness of edges that remains noticeable at the screen rulings generally used. Very fine rulings can be used to achieve sharp edges, but this causes the printing inks to tend to bridge the dots and greatly increases the cost.